Throughout John Michael McDonagh's The Guard, you can't help but think of In Bruges; it's not just the Irish settings and the big, open face of star Brendan Gleeson, but the snappy dialogue, quick and dirty, which moves at such speed that the filmmaker takes it on good faith that audiences will keep up. The resemblance is not just superficial, it is fraternal--In Bruges writer/director Martin McDonagh is this filmmaker's brother. They put something in the water in that house.

Gleeson stars as Sergeant Garry Boyle, a Galway, Ireland cop whose morals are firmly established in a pre-title sequence in which he finds a badly wrecked sportcar, digs a bag of drugs out of one of the young victims' pockets, and cheerfully takes a hit of the lad's Ecstasy on the spot. His tiny hamlet is invaded by FBI agent Wendell Everett (Don Cheadle), and the two do not hit it off ("I'm Irish, sir. Racism is part of my culture"), but a begrudging respect eventually grows--as these things so often do--over pints of Guinness.

Everett is in town to investigate a half-billion dollar drug smuggling ring, headed up by Cornell (Mark Strong, from Sherlock Holmes). Boyle is as helpful as is convenient, inasmuch as it doesn't interfere with a prior commitment to a pair of Dublin prostitutes ("It's my day off"). But he ultimately gets involved primarily out of irritation with the criminals; when Sheehy (Liam Cunningham) tries to blackmail him, Boyle is unflappable, and when the criminal tries to pay him off to butt out, the cop is more interested in slurping down his milkshake. (He explains his distress after the encounter as the result of his ice cream headache.)

Boyle is genuinely compelling lead character: overflowing with vices, yet somehow also brave and honorable. Bogart could've played him--if he were an overweight Irishman. Gleeson gives every good line an extra snap, and though the faux-Morricone mock-heroic music in the opening credits plays as a joke, by the time it returns for the climax, he's earned it. He's in nearly every scene and is both an open book and an enigma; when Everett explodes, "I can't tell if you're really motherfuckin' dumb or really motherfuckin' smart," he just smiles.

Cheadle mostly plays the straight man to Gleeson's big, boorish vulgarian, and that's the wise choice (considerably wiser than his strange accent, which sounds less like a native-born American and more like a British actor not quite pulling off an American dialect). The supporting roles are filled out nicely as well--I liked David Wilmot as the villain who insists that he's a sociopath and not a psychopath, and Fionulla Flanagan as Boyle's impish mum, and Strong (who usually plays these roles all full of straight menace) having fun with his character's impatience and existential angst.

McDonagh has a snazzy directorial touch; he eschews the standard muddy browns and greens and goes for a louder and more amusing look, and even his framing is often funny, the dry wit of the enterprise translating to his compositions. The real attraction, though, is the script, which cranks out spot-on send-ups of standard scenes (during a money handoff, Strong is asked if "it's all there," to which he spits back, "No, I skimmed a couple of grand off the top--of course it's all there... This is a payoff, that would defeat the entire purpose of the transaction!") and character comedy in equal proportion.

The Guard may be dismissed, as In Bruges was in some quarters, as yet another riff on the Tarantino talk-talk-bang-bang school of screenwriting, but McDonagh has a unique voice in his dialogue, which is a clever mix of insults, callbacks, put-ons, understatements, and cheerfully inventive profanity. It's a smart, funny, dark little treat of a movie, and Gleeson is a wickedly enjoyable leading man.